Cardiovascular function during surgery
Our laboratory has several ongoing areas of basic sciences and clinical research. Clinically, a major focus has been in the field of blood conservation. Emphasis has been placed on the development and application of new techniques and pharmacologic interventions, as well as on the reevaluation and optimization of pre-existing techniques. The recombinant red cell growth factor erythropoietin is being used to stimulate perioperative red cell production, with emphasis on optimizing the dose-response relationship, so that maximal acute preoperative marrow stimulation can be achieved. The serine protease inhibitor aprotinin is being used to improve perioperative hemostasis; in addition, its relative effects on platelet, coagulation, and white cell compartments of blood are being investigated. Intraoperative autologous donation, also known as acute hemodilution, is being evaluated in respect to its effects on red cell preservation and postoperative bleeding. The effects of the CPB apparatus on red blood cells, and other methods of red cell preservation, serve as additional areas of investigation. The benefit of minimizing cardiopulmonary bypass circuit prime volume (to minimize hemodilution) is being evaluated in a prospective randomized trial. A series of investigations are being made into determination of the lowest safe red cell transfusion trigger during cardiopulmonary bypass. Both retrospective and prospective databases relating the incidence of stroke and neurocognitive injury are being utilized in these determinations.

As each blood conservation technique and pharmacologic agent is evaluated and its application optimized, it is being integrated into a comprehensive "state of the art" blood conservation program. Approval and funding for a prospective trial utilizing this program in 100 consecutive CABG patients has recently been obtained. This comprehensive multimodality blood conservation program is also being applied on an ongoing basis to all Jehovah's Witnesses undergoing cardiac surgery at our institution. Finally, the success of all of our blood conservation efforts has prompted us to compile a reference text, to be published by Springer-Verlag, that will hopefully allow dissemination of this knowledge, and more widespread application of blood conservation throughout the world.